1. CSE 598A Project Proposal James Yockey
Pipeline ADC
CSE 598A Project Proposal
James Yockey

2. Analog to Digital Converters
Review: What does an ADC do?

3. Types of ADC
Flash
Pipeline
Others…

4. Flash ADC

5. Pipeline ADC

6. Pipeline ADC (cont.)
Using two bits for a signal that can vary from 0 to 5V, we can divide it into 4 regions. For example:
00 = 0 to 1.25
01 = 1.26 to 2.5
10 = 2.6 to 3.75
11 = 3.76 to 5.0

7. Pipeline ADC (cont.)
Assuming each stage produces one bit of output, we need two stages.
Stage one will check if the MSB is 1, i.e. the input is greater than 2.5
If it is, the bit is set to one, and the subtractor subtracts 2.5 from the input.
Stage two will check if the LSB is 1, the incoming voltage is greater than 1.25.
Example: If 3.0V is the input, the MSB is 1, and the voltage sent to stage two is 0.5V
Stage two checks to see if the voltage is greater than 1.25
The output bits are 1 0, which is the correct value.

8. Pipeline ADC (cont.)
We can design all of the stages to be identical if with the use of an amplifier.

9. Other types of ADC Folding Time-interleaved Algorithmic Interpolating
Integrating-type
More information can be found at:

10. Why pipelined? Less comparators than flash Smaller Less power
Flash uses 2n, pipelined uses # stages
Smaller
Less power
Resistor ladder difficult to implement in CMOS
Slower than flash, but still high speed

11. Application What can we use this for? When completed, may be used for:
Software defined radio
Ultrasound pill
Others…

12. Priorities for design In order of importance, highest first: Speed
Accuracy
Error correction
Power
Area

13. Specifications Average Project Samples/sec (MS/S) 368 200 Bits 10
Differential Nonlinearity
Unknown ≤1
Integral Nonlinearity
Power (mW)
222
Area (mm2)
2.4
1.8

14. Project Schedule Week Tasks Comments Week 1
Circuit research and design
Week 2
Week 3
Schematic entry
Week 4
Simulation/Test
Spring Break
Week 5
Layout
Project Progress Presentation
Week 6
Week 7
Week 8
Week 9
Final adjustments
Project Final Presentation

15. Conclusion
Any comments or questions?